Electric motors are used for high-speed actuation and as traction motors in various applications. In both applications, reducing size, inertia, and cost are important. Substantial cost is also involved in the power electronics which drive the motor. Furthermore, it is normally required to build a mechanical ratio between the motor and the load in order to translate high motor speeds into useful work.
Known electric motors typically convert electromagnetic force into rotary motion. Some known electric motors use a crank shaft to translate linear core movement into rotation of a shaft. The preceding configuration limits a ratio between axial and rotary motion and also fixes the ratio. A further problem with known designs is the large number of solenoid coils used, which increases the complexity and cost of the motor and associated power electronics for the motor.